The invention relates in general to a system for scanning vibrations of a mass, and for converting such mechanical vibrations, particularly of strings of musical instruments such as guitars, harps, pianos, and the like, into corresponding alternating electrical signals.
In a scanning system of this kind disclosed in German DE-OS 29 16 684, a part of the vibrating body is arranged in the path of a light beam and cooperates with a stationary body in such a manner that a gap is created between the vibrating and stationary bodies. This gap is variable in accordance with the vibrations of one of these bodies, so that, depending on the amplitude of the vibrations broad or a narrow strip is illuminated on the active surface of a converter. According to the size of the activated surface of the converter the corresponding voltage signals are generated. This known scanning system, however, permits only the scanning of such mechanical vibrations whose amplitudes are directed to the stationary body. Vibrations occurring in another plane oriented in the longitudinal direction of the gap between the vibrating and stationary bodies can be detected only by using two converters with two light gaps arranged at right angles one to another. Even in this arrangement it is possible to scan vibrations in respective planes only, whereas scanning of vibrations in longitudinal direction of the light beam is not possible.